The steam jet ejector is formed of a convergingdiverging nozzle, a convergingdiverging diffuser, a throat, a mixing zone, and a suction or entrainment chamber, fig. Very often, the motive fluid is steam and the device is called a steam jet ejector. Steam jet ejectors for the process industries 2005 edition open. One of a plants greatest energy users can be its steam driven turbines. Single and multi jet steam compressors are equally as efficient in a broad range of applications. The mass of highvelocity steam is discharged from the nozzle in a directed flow through an air chamber and into a convergentdivergent. General construction standard for ejector componenets. In an ejector, a working fluid flows through a jet nozzle into a tube that first narrows and then expands in crosssectional area. Download application of steam jet refrigeration system pdf. It is a fluiddynamic pump with no moving parts, excepting a valve to control inlet flow.
In order to achieve the best operating costs, the steam jet pumps are designed for all the process conditions in the plant. Steam turbines have excellent reliability and durability and are used to drive pumps, compressors, generators, and other rotating mechanical equipment throughout the refining, chemical, and petrochemical industries for processes that produce. Since 1979, nash has manufactured the most efficient, reliable hybrid vacuum systems. The motive steam velocity becomes larger than the speed of sound supersonic as it leaves the nozzle. Depending on the specific application, an injector is commonly also called an eductor jet pump, a water eductor, a vacuum ejector, a steam jet ejector, or an aspirator. Basic ejector components are the steam chest, nozzle, suction, throat, diffuser and they discharge fig. Performance optimization of steam jet ejector using cfd. Ejector design calculation pdf download unger i hedmark l. Steam turbines have excellent reliability and durability and are used to drive pumps, compressors, generators, and other rotating mechanical equipment throughout the refining, chemical, and petrochemical industries. Steam jet ejectors for the process industries mcgrawhill chemical engineering power, robert b.
Nash ejectors have the ability to handle large volumes at very high vacuum levels, and can be optimized to contribute to process enhancements and operational efficiency. Ejectors general ejector parts, nomenclaturewith the view of stablishing standard terminology, the four sketches in fig. Addition of the tank of steam jet refrigeration system, but maybe it avoids control is to. Pdf design, cfd analysis and performance evaluation of. Large industrial plants often vent significant quantities of lowpressure steam to the atmosphere. A vacuum ejector, or simply ejector is a type of vacuum pump, which produces vacuum by means of the venturi effect. Edwards custom engineered products cep group, evolved from the acquisition of hick hargreaves, can provide you with equipment and turnkey services for your oil and gas, petrochemical, power generation, cpi and associated industry applications.
Modern, energy efficient steam jet ejector systems offer many advantages when compared with. This thesis focuses on finding the optimum operating pressures for a hybrid steam jet ejector system and a hybrid turbocompressor system. Steam ejectors process equipment steam ejectors steam ejector systems the first steam ejectors were developed in the early 1900s. The steam nozzle through which the propelling steam expands and converts its pressure energy into kinetic energy 3. Steam jet ejectors for the process industries by robert b.
The fluid leaving the jet is flowing at a high velocity which due to bernoullis principle results in it having low pressure, thus generating a vacuum. Steam jet ejectors were for many years the workhorse of the chemical process industries for producing vacuum. A complete guide to getting the best from steam jet ejectors. Steam jet ejectors for the process industries 2005. Combining low capital cost, simple operation, high reliability and the ability to handle large volumes at very high vacuum levels, they can be optimized to. Vacuum ejectors are used in a variety of applications in the process industries, such as food and beverage, chemicalpetrochemical, waste reduction, pharmaceutical, nutraceutical, power and energy, and.
They were initially used to eject air from condensing plants on turbine systems. They are also used for continuous removal of air from surface condensers, in order to maintain desired vacuum pressure on condensing vacuum turbines. Unique systems designs and manufactures process vacuum systems including condensers, steam jet ejectors, liquid ring vacuum pumps and hybrids along with instrumentation, complete automation and auxiliary equipment. Their more compact design cuts down on weight and space requirements. Multistage, steam jet vacuum systems, mixing condenser. Multi jet steam compressors are used in evaporators for the food industry in particular. We also lead the industry in the duplication of parts and assemblies for rotating equipment such as steam turbines, compressors and more. Key design considerations for vacuum process condensersopen file 2. How to calculate the flowrate of motive fluid in an ejector free downloadpdf file. Applications for steam ejectors increased throughout the 20th century and today edwards has with many years of experience in the design, manufacture and supply of steam ejector systems to many demanding applications in the process industries. Download application of steam jet refrigeration system doc. Steam jet ejectors offer a simple, reliable, lowcost way to produce vacuum. Steam jet compressors, jet pump, thermocompressor, ejector.
It should be noted, however, that these sketches are merely illustrative for the purpose of indicating names of parts. Applications range from coarse vacuum single stage steam ejectors. Ejectors are considered an alternative to mechanical vacuum pumps for a number of reasons. The steam chest through which the propelling steam is admitted 2. Because operating conditions may change during the operating life of the geothermal power plant, the motive steam nozzles for steam jet ejectors should be replaceable. In this investigation, an experimental steam ejector system was designed and constructed to investigate the performance of the ejector system with water as the working fluid at steam generating.
A steam injector is a typical application of the principle used to deliver cold water to a boiler against its own pressure, using its own live or exhaust steam, replacing any mechanical pum. Principal applications for steam tlv a steam specialist. The model makes use of the field data collected over 35 years by power 1994 for vapor entrainment and compression ratios of steam jet ejectors. The industry standard for removing these noncondensable gases has been steam jet ejectors or a hybrid system of steam jet ejectors and liquid ring vacuum pumps. An injector is a system of ducting and nozzles used to direct the flow of a highpressure fluid in such a way that a lower pressure fluid is entrained in the jet and carried through a duct to a region of higher pressure. Pdf thermal analysis of steam ejector using cfd dr p. For undated references, the latest edition of the referenced documents including any. They are widely used to generate vacuums with capacity ranges from very small to enormous. In oil and gas processing industries the name vacuum pump is conventionally. The steam jet ejector is modeled by the semiempirical model developed by eldessouky 1997. A feasibility study of steam jet refrigeration, int. Through the acquisition of hick hargreaves in 2001 edwards have been instrumental in the development of. The nash ener jet hybrid vacuum system combines the stability of our liquid ring pumps with the high vacuum capabilities of our steam jet ejectors resulting in a hybrid vacuum system that reduces ghg emissions and operating costs while improving system stability.
Introductiona steam ejector is a device which utilizes the momentum of a highvelocity primary jet of vapour to entrain and accelerate a medium in still or at a low speed. Use steam jet ejectors or thermocompressors to reduce venting. With increasing emphasis on stricter pollution control, their use was curtailed. Nov 16, 2020 steam jet ejectors for the process industries by robert b. In order to achieve the best operating costs, the steam jet pumps are designed for all the process conditions in. The steam nozzle through which the propelling steam expands and. Pdf experimental investigation of steam ejector system. Produced exclusively in the usa and maintained across the globe, jet vac technologies has revolutionized the vacuum industry processes, by delivering safe, costeffective. Steam jet ejectors for the process industries 1994. Jet ejectors are popular in the chemical process industries because of their simplicity and high reliability. Saving energy and reducing a plants carbon footprint is vitally important in todays world. Jet ejectors are popularly used in the chemical process industries because of their simplicity and high reliability.
They will handle both condensable and noncondensable gases and vapors as well as mixtures of the two. This reduced pressure vacuum induces flow of gas from a chamber or process, discharging to atmospheric pressure, to a condenser or to a subsequent stage. Incidentally, if one steam ejector with a relatively clean nozzle is operating in parallel with a jet with a fouled nozzle, the good jet will extract motive steam out of the fouled ejector and greatly degrade the efficiency and capacity of the clean ejector. Case study steam jet ejector free download as powerpoint presentation.
Swinging doors or is steam jet refrigeration is low cost than an ejector refrigeration for your browser to reject heat source with or just a point. Modern, energy efficient steam jet ejector systems offer many advantages when compared with other vacuum producing systems. Steam ejectors provide vacuum in many process industries and utility companies. To improve the efficiency of the simple ejector cycle more complex cycles have been investigated 5 as well as the integration of ejectors with vapour compression and absorption systems. Pdf experimental investigation of steam ejector system with. Steam jet ejectors operating principles steam jet ejectors operate on a massvelocity principle. The important functions of an ejector include maintaining vacuum in evaporation, removing air from condensers as a vacuum pump, augmenting thrust, and increasing vapour pressure as a thermal compressor. The primary advantage of installing ejectors versus mechanical pumps is the ejectors simplicity of operation, low first cost and ability in handling wet. In this study, semiempirical models are developed for design and rating of steam jet. Scribd is the worlds largest social reading and publishing site.
Steam ejectors use steam or gas instead of moving parts to compress a gas. Key design parameters the compression ratio of the injector, is defined as ratio of the injectorss. Two energy processes and the shockmixing layer were. Steam jet ejectors are used in the process, food, steel and allied industries in connection with such operations as filtration, distillation, absorption, mixing, vacuum packaging, freeze drying, dehydrating and degassing. The outer tube then narrows into a mixing section where the high velocity working fluid mixes with th. In this paper, the steam jet ejector was designed and then the cfd analysis was carried out for the geometry and the inlet condition data verified by the performance evaluation of the jet ejector. Steam jet ejectors are an essential part in refrigeration and air conditioning, desalination, petroleum re. Role of the time of steam jet refrigeration system are concerned with an indirect system produces cooling of all types but the difference is a liquid. Thermo compressors are ejectors applied to recompressing spent steam and process fluids. Ejectors and steam jet ejectors document library graham. The steam or air converts that pressure or potential energy to velocity or kinetic energy.
Ejector or jet pump refrigeration is a thermally driven technology that has been used for. Steam jet ejectors educt process gases into the steam chest and then through a specially understand realworld problems of vacuum ejector performance use these guidelines and case histories to evaluate and troubleshoot. Understand realworld problems of vacuum ejector performance. Process vacuum and jet ejector systems jetvac technologies.
Distance between steam nozzle and diffuser throat set wrong the distance between the. Used extensively throughout the process industries, steam ejector vacuum systems offer a reliable and economical means of handling high volumes of gas and vapor streams at low pressures. Multistage steam jet vacuum systems korting hannover ag. The motive steam, m m, expands in the nozzle from state 1 to state 3, where its static pressure energy is converted to kinetic energy. Convert pressure to velocity without moving parts jet vac two stage hybrid steam jet. Steam jet ejectors for the process industries 2005 edition. In reference to figure 1, there are the following parts. For over 65 years, jet vac technologies has been providing customers with custom vacuum solutions to help solve and provide efficient, reliable, process vacuum systems. Selecting steam jet pumps as vacuum generators ensures a high level of reliability in the plant as a whole, while main tenance costs are kept to a minimum. Nash steam jet ejectors and systems have been an industry benchmark since 1979, and are recognized worldwide for delivering reliable performance and lower emissions.
Steam jet ejectors are used to pull vacuum on process equipment such as distillation towers to separate and purify process vapor streams. Nash has been designing, manufacturing and troubleshooting steam jet air ejector systems since 1986. Steam jet ejectors at geothermal steam plants are typically fabricated from type 316l stainless steel to resist corrosion from the noncondensable gas and steam mixture. Steam jet ejectors pardee steam jet ejectors use the pressure energy that is available in moderate pressure steam traditionally 90150 psig to create subatmospheric pressure. The compression ratio, cr, is the pressure ratio of the compressed and entrained vapors. Crude oil refining and petrochemical industries make extensive use of. Performance optimization of steam jet ejector using cfd a. The propelling steam expands through a divergent nozzle, converting its pressure energy into velocity energy. Steam jet ejectors for the process industries mcgrawhill chemical. A steam ejector refrigeration system powered by engine. No source of power is required other than the motive gas. They are especially effective in the chemical industry where an onsite supply of the highpressure motive gas is available. There are still many applications, however, such as those with large capacity requirements, where ejectors are the only equipment that can produce. Steam jet ejectors for the process industries 1994 edition.
The ejectors form an integral part of distillation columns, condensers and other heat exchange processes. Multistage steam jet vacuum systems with surface condensers. Reliable vacuum service for the process industries. Steam flow to an ejector must be maintained at the design rates, otherwise vacuum column operating pressure may increase. Pdf design, cfd analysis and performance evaluation of the. A steam jet ejector is a simple device that uses pressurized steam to create a partial vacuum inside an enclosed system by pumping gases and vapors out of the system. Due to their simplicity, constantpressure jet ejectors that. Steam jet ejectors for the process industries mcgrawhill.
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